Posted
by
Soulskillon Friday July 18, 2014 @11:39AM
from the partly-hairy-with-a-chance-of-eyeballs dept.

An anonymous reader writes "Scientists may not be able to predict what life will be like 100 million years from now, but they may be able to make short-term forecasts for the next few months or years. And if they're making predictions about viruses or other health threats, they might be able to save some lives in the process. "Biologists have found cases in which evolution has, in effect, run the same experiment several times over. And in some cases the results of those natural experiments have turned out very similar each time. In other words, evolution has been predictable. One of the most striking cases of repeated evolution has occurred in the Caribbean. ... Each time lizards colonized an island, they evolved into many of the same forms. On each island, some lizards adapted to living high in trees, evolving pads on their feet for gripping surfaces, along with long legs and a stocky body. Other lizards adapted to life among the thin branches lower down on the trees, evolving short legs that help them hug their narrow perches. Still other lizards adapted to living in grass and shrubs, evolving long tails and slender trunks. On island after island, the same kinds of lizards have evolved."

TFS makes me think that it's an article about covergent evolution. That's not exactly news. The kiwi looks like a mouse. water dragons look like iguanas. animals look like the role they fill in the ecosystem.

The thing is, they're filling the same roles in the same ecosystems. Suppose trees were square on one island, or very sticky on another, or very short and smooth, or poisonous, or covered in ants. In these cases the lizards would have evolved very different forms.

That's the point. When they know certain conditions, they can predict, with some level of accuracy, what evolutions will take place.

I'm just curious as to how they overcame the more unpredictable factors such as random mutations (e.g. a cosmic ray bumps some life form's DNA a little, causing a benefit, etc.), or did they just count that as statistical noise, or...?

That's only the case when there are a limited number of ways to adapt successfully to a changed condition. What this seems to show is that there are is not a limited number of ways, at least a preferred number of ways. Which means that the mutations necessary to adapt to them don't occur at random.

There are a couple of ways this could be done, but the reasoning isn't straightforwards. OTOH, if you instead can say "Well, the last time this situation occurred, that was the response", and make a correct pre

water dragons (Physignathus cocincinus) are a lizard found in southeat asia. They are omnivorous and fill roughly the same role there that iguanas fill in south america. They share a lot of physical traits, and to the untrained eye are often confused for each other (though with a little experience, it's easy to tell them apart)

The difference, of course, is in demonstrating the predictive value of evolution, in a measurable and falsifiable way. Before, we could make pretty reliable predictions about unknown past events, which is good enough to be science, but sciences' main draw is in its utility in being able to understand how things will happen under any given circumstance.

It does not appear to be quite the same thing as convergent evolution (but I'm a physicist not a biologist!). My understanding of covergent evolutions is that it is when two wildly different evolutionary paths end up with the same solution to a problem e.g. an octopus eye and a human eye are functionally very similar even though our last common ancestor certainly had nothing like it.

This is rather the claim that evolution is reproducible in the short term i.e. if you put the same strain of bacteria in the same conditions they will evolve in the exact same way and not find different evolutionary paths to the same goal. This means that evolution becomes predictable and you can then predict with some degree of accuracy how a virus, bacteria or cell will evolve. This has obvious applications for disease control and perhaps cancer too.

But it is the same forces in play. The limitations of the physics (and thus chemistry and thus biology) that drive structure and function of DNA, protein, etc limit the possible ways that nature can create ways to solve evolutionary problems. So whether it is a photon sensing system or pads on lizard, given the toolkit that nature (yeah, I'm anthropomorphizing a bit, sorry) has, it uses it in a similar fashion to get to a desired end result.

Also not an evolutionary biologist, but I think you're on the right track. I don't know whether a given environment will favor a specific set of mutations (e.g., the exact same path each time), but assuming a constant environment, the organisms that result will probably be similarly adapted to the environment. It's kind of a cool idea because at a molecular-genetic level, there are probably something like functions (vs individual lines of code) which interact and can be documented at some sort of macro l

I'm thinking this is also about what we consider "alike" or "the same" Just a few days ago, I came across a report of a new (to me) member of the Burgess shale fossils, a relative of Anomalocaris. Basically, Anomalocaris was a two meter long killer shrimp with spiky grabbers and rasping plate teeth. It was the biggest thing in the ocean, the equivalent of a whale compared to the typial creatures of the time. This particular relative was a very large sized ( for the era) filter feeder, believed to be evolved

I'm thinking this is also about what we consider "alike" or "the same"

Sort of but I'm thinking that it is more about the process vs. result. Convergent evolution is about the end results: there appear to be only a certain number of basic eye designs which work and so evolution tends to converge on one of these solutions no matter where it starts. This result is talking about the fact that given the same starting point and the same environment identical organisms will evolve in the same way i.e. there are not just stable solutions which you arrive at but stable paths along wh

Perhaps not necessarily. Lenski's E. coli long-term evolution experiment has demonstrated that some evolutionary steps can be "pre-conditioned". That's what *I* thought immediately of when I saw the summary: that given a current state of a species, it might be possible to predict the likeliest changes to expect.

Determinism is the philosophical position that for every event, including human action, there exist conditions that could cause no other event. Wikipedia [wikipedia.org]

It's the simple assertion of effect derives from cause. This bears absolutely no relationship to teleological philosophical arguments, which construe reality itself to be purpose driven. Outright unrelated concepts. You need to educate yourself.

Yeah, I'm going to back out of this debate and call you a moron, instead. You've just made it very clear that you have a stupid position and that relatively simple definitions have no bearing on how you interpret words.

I think that convergent evolution would be a very high-level example of how the results of selection can be predictable and are in fact repeated, even if the actual underlying mechanisms and specific genes involved in the convergent adaption in different species differ, the results are the same.
Recurrent evolution also seems to support the "non-random" or "predictable" nature of evolution.
In other words, if you put a square organism in a round environment, we know that its successful decedents will have

No. Convergent evolution deals with appearance or function, not with genetics, details of implementation, etc.

The classic example of convergent evolution is the icthyosaur and the dolphin. Both have LOTS of similarities in form and shape. The details of their function are different, but you need to look fairly closlely to see that. E.g. the Icthyosaur had huge eyes where the dolphin has sonar. The two animals have the axis of their tails at right angles to each other, etc. But you can trace the axis o

Sure, in close islands with identical ecosystems. But if this hypothesis scales universally.... why don't we have kangaroos or elephants in the Americas?

Not enough scaling. We're just talking about lizards turning into other lizards. There's nothing like an elephant that could turn into one on the same kind of time scale. Genes can't do just anything, only some possible outcomes are valid, and there was nothing which could turn into those things during that time. Also, different pressures. In the lizards-on-islands example, the pressures faced by the lizards are similar, down to respective environments, predators, etc.

No, the point was if they knew what the conditions were like they may be able to predict short term changes based on being able to reproduce the same results multiple times in a identical ecosystem. Not that kangaroos and elephants would evolve in a place different from their natural habitat...

of biological systems to mutation more than anything else. Without mutation you will just see the permutations of the existing genome try to fill the ecological space with those best suited to particular niches taking up residence there. The lizards for example the best suited fro tree climbing/feeding take up residence in the trees and breed new generations with an ever more narrow slice of the original colonizers genome.

The beneficial mutations that introduce new genes are were you get changes and would